Combination Lock Dial Position Guess Trainer
Modern mechanical "top reading" safe dials are frequently referred to as "anti-spy". Such dials are intended to make it harder for a bystander to observe the combination when the safe is opened. It is very common for such anti-spy dials to include a day locking feature that incorporates a lock cylinder on the face of the dial. With a bit of practice, it is possible for a chicanerous bystander to come pretty close to determining the combination by observing the position of this cylinder as the safe is opened. The design of most Group II mechanical locks such as the S&G 6730, 6741, and 6630 allows the third digit to be determined without redialing the first two numbers. A "three number" combnation lock is effectively a "two number" lock if one knows this rather unsophisticated technique. This simulation gives you a chance to measure, and refine through practice, your skills at determing the dialed number by observing the front of a so-called "spy proof" dial.
	The green numbers show the position of the dial when the day lock sylinder (shown in gray) is aligned with that position on the dial. You will be able to guess a number when shown a similar image without the dial numbers. This is to test and perfect your ability to determine the dialed number by observing the position of the day lock cylinder as someone else opens the safe.

Combination Lock Dial Position Guess Trainer

Modern mechanical "top reading" safe dials are frequently referred to as "anti-spy". Such dials are intended to make it harder for a bystander to observe the combination when the safe is opened.

It is very common for such anti-spy dials to include a day locking feature that incorporates a lock cylinder on the face of the dial. With a bit of practice, it is possible for a chicanerous bystander to come pretty close to determining the combination by observing the position of this cylinder as the safe is opened.

The design of most Group II mechanical locks such as the S&G 6730, 6741, and 6630 allows the third digit to be determined without redialing the first two numbers. A "three number" combnation lock is effectively a "two number" lock if one knows this rather unsophisticated technique.

This simulation gives you a chance to measure, and refine through practice, your skills at determing the dialed number by observing the front of a so-called "spy proof" dial.

The green numbers show the position of the dial when the day lock sylinder (shown in gray) is aligned with that position on the dial.

You will be able to guess a number when shown a similar image without the dial numbers.

This is to test and perfect your ability to determine the dialed number by observing the position of the day lock cylinder as someone else opens the safe.